(PO90) Photomechanical Investigation on the Impact of Endodontic Cavity Designs

Abstract: Conservative endodontic cavities aim to preserve as much tooth structure as possible to maintain the structural integrity of root-filled teeth. The objective of this study was to evaluate the effect of access cavity designs on the microstrain formed at the crown and cervical dentin under different mechanical loads using digital moiré interferometry (DMI). Six freshly extracted human mandibular first molars (N=6) were included in the study. Sagittal and coronal radiographs were used to characterize the pulp chamber anatomy prior to the experiment. Specimens were subjected to physiologic levels of compressive loading of 10, 20, 30, 40, and 50N for each group. DMI fringe patterns were acquired three times for each specimen: prior to endodontic cavity preparation (control group (CG)), after constricted access cavity preparation (CEC), and following traditional access cavity preparation (TEC). The acquired fringe patterns were subjected to digital image analysis to determine the microstrain patterns at the coronal and cervical dentin. The data were analyzed qualitatively and quantitatively using one-way ANOVA and T-tests (p = .05). The intact crowns of CG teeth showed more microstrain, which was tensile in nature, while the crowns of teeth with CEC and TEC showed more microstrain, which was compressive in nature. There were significant differences between both the coronal and cervical microstrain in the CG, CEC, and TEC groups. Our findings showed distinct differences in the biomechanical response of mandibular molar teeth with varying endodontic cavity designs, resulting in marked increases in strain at both the coronal and cervical levels relative to the intact teeth.